This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This is to develop and test large-angle rotation geometry (LARG) using monochromatic X-ray for time-resolved studies of irreversible reactions. LARG requires one and only one reaction initiation for each crystal followed by continuous probing during the large-angle rotation. This geometry greatly reduces the number of crystals required by pump-probe methods.